Modeling of diffusion and oxidation in two dimensions during silicon device processing

Abstract

A process simulator named '2D-DIFFUSE' has been developed where the coupled diffusion equation of dopant impurity and point defects: interstitials and vacancies, has been solved numerically in two-dimension. The interaction of point defects has been modeled assuming quasi (i.e. local) equilibrium, CICV = CI*CV* and constant vacancy, CV = CV*, conditions. Indeed, these two assumptions decouple the two point defects diffusion equations. The processes modeled in the present version of the simulator include pre-deposition, diffusion and oxidation. The simulator is quite successful at modeling each process individually as well as integrating various processes and models. The program has also been applied to the simulation of phenomena as the dopant diffusion under various ambients, oxidation enhanced and retarded diffusion, emitter push effect etc. Comparisons between simulation based on point defect parameters from various sources have been made.